1. Technical Field
The present invention relates to an electrophoresis dispersion liquid, an electrophoresis sheet, an electrophoresis device, and an electronic apparatus.
2. Related Art
In general, it is known that when an electric field acts on a dispersion system in which fine particles are dispersed in a liquid, the fine particles move (migrate) in the liquid due to Coulomb force. This phenomenon is referred to as electrophoresis and, in recent years, an electrophoresis display device where the desired information (image) is displayed using electrophoresis has attracted attention as a new display device.
The electrophoresis display device has characteristics such as having a display memory property in a state where the application of voltage is stopped, a wide viewing angle, and a high contrast display performance with low power consumption.
In addition, the electrophoresis display device is a non-emissive type device which also has a characteristic of being better for the eyes in comparison with emission type display devices such as cathode ray tubes.
Such electrophoresis display devices are known to include a device which is provided with a liquid in which electrophoretic particles are dispersed in a dispersion medium as an electrophoresis dispersion liquid arranged between a pair of substrates which have electrodes.
In the electrophoresis dispersion liquid formed in this manner, particles including particles with a positive charge property and particles with a negative charge property are used as the electrophoretic particles, due to this, it is possible to display the desired information (image) by applying a voltage between the pair of substrates (electrodes).
In general, particles provided with a coating layer where a polymer is linked with respect to a substrate particle are used as the above electrophoretic particles and forming the particles to be provided with the coating layer (polymer) in this manner makes possible to disperse and charge the electrophoretic particles in the electrophoresis dispersion liquid (for example, refer to JP-A-2015-055860).
In an electrophoresis display device provided with an electrophoresis dispersion liquid as described above, high reflectivity characteristics and fast display characteristics are important display characteristics. However, for example, in JP-A-2015-055860, in order to obtain excellent white reflectivity when displaying white, the content of the electrophoretic particles in the electrophoresis dispersion liquid is approximately 40 weight %. However, although it is possible to obtain excellent white reflectivity under the condition of such a high particle content, the volume occupied by the electrophoretic particles is increased and the viscosity of the electrophoresis dispersion liquid is increased as a result. Therefore, during migration of the electrophoretic particles when changing the image, resistance is generated by the contact between the electrophoretic particles and, as a result, there is a problem in that the display speed of the images is reduced. That is, in the electrophoresis display device, high reflectivity characteristics and fast display characteristics are opposing display characteristics.